In many electronic applications, such as destination guidance or navigation systems for vehicles, telephone systems or audio/video players, a user usually has to select one or more list elements from a database. In the case of a navigation system, for instance, the list elements may correspond to city names, street names or house numbers. Many of these systems can be speech guided or speech controlled by the user, i.e. the user can select a list element from the database by speaking the desired list element.
A speech recognition system for processing voice inputs from a user to select a list element from a list of list elements is known from WO 2004/077405.
For large databases, current systems can only be used to select a single element of the database at a time. Many applications, however, require to select a combination of several list elements. For example, in a navigation system it might be necessary or desired to select a combination of a city name and a street name.
Therefore, a need exists to provide a speech recognition method for selecting a combination of elements from a database using a single utterance.
A straight-forward method which could meet this need may comprise enrolling all valid combinations into a single set of list elements comprising, for instance, all city-street combinations of a given country. According to this example, such a single set of list elements would comprise several millions of entries for a country like France or Germany. Therefore, such a set may not be processed efficiently on a conventional embedded device.
It is therefore, the problem underlying the present invention to overcome the above-mentioned drawback and to provide a computationally efficient speech recognition method for selecting a combination of list elements using a speech input.